Green roofs are so so nice and the most of us, including me ask why there are not more of these sustainable roofs around in the cities of the world? There are so many advantages by making roofs green. First of all the reduction of temperatures in the cities. Yep, you heard right - normal bitumen roofs reach up to 150°F (65°C), which has a significant impact on the climate of cities. Further, green roofs can help to manage heavy rain in a more sustainable way.
"When rain falls on a conventional roof, it sheets off the city’s artificial cliffs and floods down its artificial canyons into storm drains—unabsorbed, unfiltered, and nearly undeterred."
In comparison green roofs are able to absorb the water and slow it down due to the existence of grass and soil. That could help to extend the lifetime of a city’s drain system by fewer sewer overflows. It is naturally filtered and can be used afterwards for certain scenarios or just returns to the drain system in a more cleaner way. Further green roofs are habitable and can serve as a nice park or garden.
The problem is that setting up green roofs cost two to three times more than conventional roofs and the running costs to maintain such a “garden” area are of course higher, as well. In the long-run these costs could be covered because it is just like maintaining another floor. Dead space becomes effective area. This area can produce natural goods, serve as location for events or for other cost-covering use-cases.
Finally, it is very sure that the costs are higher, but what you get is not only a superb place with a view on your office skyscraper, but a chance to give back something to nature which makes people happy and eventually more motivated to work under such a roof.
National Geographic - Green Roofs
Intercon - One Roof, Two Roofs, Green Roofs, Blue Roofs